Colored couplers



Patented Nov. 9, 1948 COLORED COUPLERS Dudley B. Glass, Paul W. Vittum, and Arnold Weissberger, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y.,-a corporation of New Jersey No Drawing. Application May 3, 1944,

Serial No. 533,930

9 Claims.

This invention relates to color photography and particularly to coupler compounds for use in photographic processes.

Color-forming compounds which react with the development product of aromatic amino develop- .ing agents to form colored images upon photographic development are well known. Generally, these color-forming compounds or couplers are colorless or substantially colorless. This lack of color is usually desirable where the coupler is'to be incorporated in the emulsion layer and the unused coupler remains after formation of the colcred image. When the coupler is used in the developing solution, it may be colored without detriment to the final image, and some colored couplers are known, such as paraphenylazoacetoacetanilide which was disclosed in 5Mannes and Godowsky Patent 2,108,602.

We have now found a new type of coupler which may have applications in several fields. The new couplers are, in themselves, more or less strongly colored, and during the coupling reaction, the chromophore system in the coupler is broken up with the result that the original color of the coupler is destroyed and a new dye is formed. Thus, on developing an emulsion layer containing one of these colored couplers, the coupler color is destroyed, and a new color is formed by the coupling reaction, at those points where development occurs. There is formed in this way a dye image of one color on a background of another color.

It is, therefore, an object of the present invention to provide a colored coupler whose chromophore system is destroyed on coupling. A further object is to provide a novel radical-replacement type of chemical reaction. A still further object is to provide color couplers suitable for color correction processes of color phtography. Other objects will appear from the following description of our invention.

These objects are accomplished by using as the coupler an open chain reactive methylene compound having an azo group attached to the reactive methylene group. These compounds have the following general formula:

where X and Y are negative groups such as -COR, COOR, -COCOR, COCOOR, CONHR, *CsH4NO2, -CN. H j' R. is an alkyl, aryl or a heterocyclic group;

Cal

R is a substituted or unsubstituted aromatic or heterocycllc radical.

In previous descriptions of reactive methylene compounds for color photography, it has been assumed that the reactive methylene group must be unsubstituted in order for coupling with the developer to occur. We have found that the active methylene group may be substituted with an azo group and that this group is removable by the oxidized photographic developer when the azo substituted coupler is treated with the oxidized developer either in aqueous solution or in the photographic emulsion layer. Thus the coupler may be converted to a colored compound and the azo group readily removed from it by means of reaction with the oxidized developing agent. This reaction appears to proceed as follows:

where X, Y and R are the same as in the general formula above.

While wehave indicated the colored couplers as possessing an azo structure, it is also possiblethat the structure may be that of a hydrazone or some other tautomeric form or a mixture of these as indicated" by the following structures:

o o o A i-oil i-0131i l e t a 11m t u- (Phenylazo) benzoylacetonitrile 2. 00 OH C HC H C N 0 lsHn m- (2-sec.-amyl-5-carboxyphenylazo) 2-furoyl) acetonitril'e a- (2,4-dinifnophenylazo )'-befizoylacetoacetanilide oN -o H-'N=NO Phenylazomalononitrile Ethyl-ii- (phenylagoY-cyanoacetate' 6. O O O C211 G 0GH-N=N- Ethyl ii- (phenylazo -benzoylacetate 7. (l3 0 C Ha c'o c H'N=N;

(Phenylazol '-acetylbeiizoylmetliaiie '8. 5

Phenylazo dibenz0ylmethane 9. G 0-60 0 C 2115 Ethylii- (phenylazo -ethoxalylacetat'e a- Z-quinolylazo -bcnzoylacetanilide (1-phe11yl-2,3-dimethyl-4-azopyrazolyl) -2-naphthoylacetonitrile 1,4-diphenyl-2-phenylazo-1,3,4-triketo butane -CH CN 2- [m- (4-methoxyphenylazo) -cyanoacetyl] -5- [N-pheuyl-N- 'y-phenylprop'yl -sulfamyl] -coumarone l7. CtHu c 0 NHGS on y- 3 30 o-i H-N=N 2 a (2 -sec. amyl-5"ca1'boxyphe1iy1azo -cyanoacetyl phenyl) -sulfamyl] -acetanilide din CH (3N is 11 2- I 02- 2"'-se'c. amyl-5'-carboxyphenylazo) -cyanoacetyl] couma'rone Our compounds may be incorporated in the photographic developing solution or in the emulsion layer according to their intended use and diffusion characteristics. In the specific examples listed above, Nos. 13, 14, 16, 1'7 and 18 are suitable for use inthe emulsion layer. When incorporated in the emulsion layer, the compounds may be added directly to the silver halide emulsion as the sodium or other Water-soluble salt, or they may be incorporated in a coupler solvent as described in Mannes and Godowsky U. S. Patent 2,304,940 or Jelley and Vittum U. S. Patent 2,322,027.

The compounds employed according to our invention may be produced by any suitable method, such as by reaction of the reactive methylene compound with the appropriate diazonium compound. For example, compound No. 2 was prepared as follows;

Three and one-half. grams (0.017 mole) of 3-amino-4-sec. amylbenzoic acid were dissolved in a mixture of 3000. of water and 6 cc. of concentrated-(hydroehlor-ic acid and theresulting solution was cooled to -0 C. One and two-tenths gramsmo lflmole) ofsodiumnitrite were added and the mixture was stirred slowly at zero degrees for thirty minutes. This solution of the diazonium salt was added. to a solution of 2.3 g. (0.017 mole) of Z-furoylacetonitrile in 50 cc. of water which contained 5 g. of sodium hydroxide. After standing for two hours, the alkaline reaction mixture was filtered and then made acid with 12 cc. f concentrated hydrochloric acid. The mush was stirred well and the precipitate was removed by filtration, washed with water and dried in air. Yield 5.8 g. (97%). After recrystallization from acetic acid, the product melted at 209 (decomp.). The preparation of the following compounds is described in Ber. Volume 21, on the following pages:

Compound 6, page 2120 Compound 7, page 1705 Compound 8, page 1703 Compound 11, page 1705 The preparation of compound 9 is described in Ben, volume 25, page 3451. The preparation of compounds 4 and 5 is described in Ber., volume 38, pages 2273 and 2266, respectively. The preparation of compound 10 is described in J. Chem. Soc, volume 43, page 111.

Our compounds are particularly useful in a process such as that of Hanson U. S. application Serial No. 538,910 filed May 33, 1944, now Patent No. 2,449,966, September 21, 1948. The Hanson process involves a color correction method in which a colored coupler is incorporated in the photographic emulsion layer prior to exposure and upon development is converted into a colored image where the layer was exposed. The coupler remaining in the unexposed portions of the layer retains its original color, and by suitable choice of the color of the originalcoupler and the color of the final dye image, a masking or correction effect can be obtained.

Various photographic developing agents can be employed with the couplers of our invention. The primary aromatic amino developing agents are generally suitable including the phenylenedia mines and the aminophenols; The alkyl phenylenediamines may be substituted in the amino group as well as in the ring. Suitable compounds are diethyl paraphenylenediamine, monomethyl paraphenylene-diamine, dimethyl paraphenylenediamine and paraaminophenol. These compounds are usually employed in the salt form, such as the hydrochloride or the sulphate, which are more stable than the free amines. All of these compounds have a primary amino group which enables the oxidation product of the developer to couple with the color-forming compounds to form dye images.

The following developing solution is suitable for developing gelatino silver halide layers containing colored couplers according to our invention.

2 amino-S-diethyl-amino toluene H01 grams 2 Sodium sulphite do 2 Sodium carbonate do 20 Potassium bromide do 2 Water to liters 1.

It will be understood that the examples and modifications set forth herein are illustrative only and that our invention is to be taken as limited only by the scope of the appended claims.

We claim:

1. The method of developing a colored image in a silver halide emulsion layer, which comprises exposing said emulsion and developing it with a primary aromatic amino developing agent in the presence of a coupler compound having the formula:

OHN=NR where X and Y are negative groups selected from the class consisting of COR, -COOR,

COCOR, COCOOR, -CONI-IR., C6H4NO2, and CN, R. is selected from the class consisting of alkyl, aryl, and heterocyclic groups and R is selected from the class consisting of aromatic and heterocyclic radicals and said coupler compound contains no other reactive CH group, and at the place of the silver image formed by the development, splittingsaid coupler compound at the azo linkage and coupling said coupler compound where the splitting occurs, with the development product of the primary aromatic amino developing agent.

2. The method of developing a colored image in a silver halide emulsion layer, which comprises exposing said emulsion and developing it with a primary aromatic amino developing agent in the presence of a coupler compound having the formula:

\CH-N=N-R' where X and Y are negative groups selected from the class consisting of -COR, --COOR,

-COCOR, -COCOOR, -CONI]IR., -C6H4NO2 and CN R is selected from the class consisting of alkyl, aryl, and heterocyclic groups and R is an aromatic radical of the benzene series and said coupler compound contains no other reactive CH group, and at the place of the silver image formed by the development, splitting said coupler compound at the azo linkage and coupling said coupler compound where the splitting occurs, with the development product of the primary aromatic amino developing agent.

3. The method of developing a colored image in a silver halide emulsion layer, which comprises exposing said emulsion and developing it with a primary aromatic amino developing agent in the presence of a coupler compound having the formula Y/CHN=N where X and Y are negative groups selected from the class consisting of COR, COOR, COCOR, -COCOOR, CONI-IR, 'C6HANO2, and -CN, and R is selected from the class con sisting of alkyl, aryl, and heterocyclic groups and said coupler compound contains no other reactive CH group, and at the place of the silver image formed by the development, splitting said coupler compound at the azo linkage and coupling said coupler compound where the splitting occurs, with the development product of the primary aromatic amino developing agent.

4. The method of developing a colored image in a silver halide emulsion layer which comprises incorporating in said layer a coupler compound having the formula:

where X and Y are negative groups selected from the class consisting of COR, -COOR,

COCOR, --COCOOR, -CONHR, CsHANOz and CN, R is selected from the class consisting of alkyl, aryl and heterocyclic and R is selected from the class consisting of aromatic and heterocyclic radicals and said coupler compound contains no other reactive CH group, exposing said layer and developing it with a primary aromatic amino developing agent, thereby splitting off the --N:N-R group in said coupler compound and coupling said compound at the point of splitting with the oxidation product of the primary aromatic amino developing agent to form a dye image, leaving said coupler compound intact in the re gions of said layer undeveloped by said. developing agent.

5. The method of developing a colored image in silver halide emulsion layer which comprises incorporating in said layer a coupler compound having the formula:

where X and Y are negative groups selected from the class consisting of COR, COOR, COCOR, COCOOR, CONHR, 'CsI-I4NO2 and CN, B is selected from the class consisting of alkyl, aryl and heterocyclic and R is an aromatic radical of the benzene series, and said coupler compound contains no other reactive OH group, exposing said layer and developing it with a primary aromatic amino developing agent, thereby splitting off the N=N-R group in said coupler compound and coupling said compound at the point of splitting with the oxidation product of the primary aromatic amino developing agent to form a dye image, leaving said coupler compound intact in the regions of said layer undeveloped by said developing agent.

6. An unexposed gelatino silver halide emulsion layer containing a coupler compound having the formula:

\CHN:NR'

where X and Y are negative groups selected from the class consisting of COR, COOR,

---COCOR-, COCOOR, CONI-IR, CsHiNOz and CN, R is selected from the class consisting of alkyl, aryl and heterocyclic groups and R is selected from the class consisting of aromatic and heterocyclic radicals, and said coupler compound contains no other reactive CH group.

7. An unexposed gelatino silver halide emulsion layer containing a coupler compound having the formula:

where X and Y are negative groups selected from the class consisting of --COR, -COOR,

and CN, R is selected from the class consisting of alkyl, aryl and heterocyclic groups and R is an aromatic radical of the benzene series, and said coupler compound contains no other reactive CH group.

8. An unexposed gelatino silver halide emulsion layer containing a coupler compound having the formula where X and Y are negative groups selected from the class consisting of COR, -COOR,

COCOR,--COCOOR, --CONHR, CsH4NO-z and CN and R is selected from the class consisting of alkyl, aryl and heterocyclic groups, and said coupler compound contains no other reactive CI-I group.

9. The method of developing a colored image in a silver halide emulsion layer, which comprises exposing said emulsion and developing it with a primary aromatic amino developing agent in the presence of a coupler compound having the formula:

where R is a carboxylic acid acyl group and R is an aryl group, and said coupler compound contains no other reactive CH group and at the place of the silver image formed by the development, splitting said coupler compound at the azo linkage and coupling said coupler compound where the splitting occurs, with the development product of the primary aromatic amino developing agent.

DUDLEY B. GLASS.

PAUL W. VITTUM.

ARNOLD "WEISSBERGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,220,065 Clarkson Nov. 5, 1940 2,220,123 Schwarc Nov. 5, 1940 2,227,981 Schinzel Jan. '7, 1941 2,263,012 Schinzel Nov. 18, 1941 2,271,230 Peterson et al Jan. 27, 1942 2,295,008 Porter et a1 Sept. 8, 1942 2,295,009 Porter et a1 Sept. 8, 1942 2,296,306 Peterson Sept. 22, 1942 2,299,641 Middleton et a1 Oct. 20, 1942 2,301,861 Downing et a1 Nov, 10, 1942 2,304,820 Hanford et al Dec. 15, 1942 2,310,943 Dorough Feb. 16, 1943 2,328,802 li-lardman Sept. 7, 1948 2,336,215 Bean Dec. 7, 1943 FOREIGN PATENTS Number Country Date 503,752 Great Britain Apr. 11, 1939 503,824 Great Britain Apr. 11, 1939 Certificate of Correction Patent No. 2,453,661. November 9, 1948.

a DUDLEY B. GLASS ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 4, lines 42 and 43, example 17, for 2-[a(2 -sec.amy1-5 -cerboxypheny1- azo)-cya.noacetyll-phenyl)sulfamy1]-acetanilide" reed a-[Q-naphthylazo-benzoyll- 4 [N-sec.-amyl-N-(4-sec.-amyl-phenyl)-suLfamyl]-acetanilide;

and that the said Letters Patent should be read with this correction therein that the ---4 same may conform to the record of the case in the Patent Office. Signed and sealed this 29th day of March, A. D. 1949.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

